My pain is similar to yours, and I have numbness at times too, which the docs say could possibly be related to desiccated and herniated discs in my cervical spine as the result of a near fatal auto accident in 1988. In fact, they think that had a lot to do with my developing fibro, although of course no one's certain of anything.
I have the pain you have and pain all over my body, pretty much everywhere, but it does seem to be worse in my arms, neck, shoulders, chest, etc. I think this is from sitting at the computer and/or using my hands, arms and neck more than other parts of my body (lifting my arms to wash my hair, for instance, is excruciating). I have difficulty walking too, but not as badly as I used to.
I know how you feel that things seem to be getting worse fast because I have felt like that many, many times, but I always bounced back (meaning that I seemed to get to a point where my symptoms weren't as severe, and I thought I was "cured" or that the docs had made a mistake).
Unfortunately, the last time I was in that position, I tried to get off disability, because I didn't want to be a drain on the system and felt like, even though I worked myself nearly to death for years and years and paid into the system, that it would be wrong to take disability.
The job was so demanding and my boss such a bully, so critical, and I was working so many hours, I had to cut back on sleep, etc., and I became extremely ill, developed an arrhythmia and hypoglycemia, adrenal exhaustion, chondroitis and all sorts of new symptoms I never had before, and then was fired while I was in the hospital. This was two years ago, and I have never "bounced back".
So if you're working, apply for disability. That's my first suggestion. As for what you're taking for pain, none of that helped me and my pain kept getting worse, so the docs were giving me injections and now, even though I avoided them for years and years (since 1988) because I had heard to many horror stories of addiction, etc., I have to rely on opioids (hydromorphone, specifically) to deal with my pain. Some days, I don't take it at all, which is what I prefer, but other times, the pain is so severe every day for a week or so, I take it the minute I get up in the morning.
As for tests, there aren't really any for fibro; but there are some that can be done to rule it out or to determine if there are other things causing your symptoms.